<!DOCTYPE html>
<html>
<head>
	<title>234</title>
</head>
<body>
	<input type="text" id="a">
	<span id='b'></span>
</body>
<script type="text/javascript">
	var obj = {};
	Object.defineProperty(obj, 'hello', {
		set:function(newVal){
			document.getElementById('a').value = newVal;
			document.getElementById('b').innerHTML = newVal;
		}
	});
	document.addEventListener('keyup', function(e){
		obj.hello = e.target.value;
	});
</script>
</html>